Composition for member preventing accretion of snow or ice and member preventing accretion of snow or ice using the same

ABSTRACT

A composition for a snow- or ice-accretion inhibiting member which has a static friction coefficient of less than 1.3 relative to snow having a temperature range of 0 to −10° C. The composition of the present invention can show not only a good snow- or ice-accretion inhabiting property upon snowfall but also an improved snow slipping-off property upon temperature rise.

This application is the U.S. national phase of international applicationPCT/JP01/01615 filed 02 Mar. 2001, which designated the U.S.

TECHNICAL FIELD

The present invention relates to a novel composition used for inhibitingsnow- or ice-accretion, that is to inhibit the gradual build-up of snowand/or ice.

BACKGROUND ART

Hitherto, in various application fields such as ships, marineconstructions, airplanes, vehicles, houses or buildings and powertransmission steel towers, a variety of ice-accretion inhibiting paintsand snow-accretion inhibiting paints have been studied in order toprevent damage due to snow coverage and icing.

In these applications, the use of organopolysiloxanes has beenfrequently proposed. The organopolysiloxanes form a water-repellantsurface because of their low surface energy due to hydrocarbon chainsregularly oriented thereon, and are free from freezing of molecularmovement even at a temperature of not more than −30° C. because of theirlow glass transition temperature, thereby preventing hydrogen bonds frombeing formed therein upon icing. For this reason, theorganopolysiloxanes are considered to exhibit a good snow-accretioninhibiting effect. Also, in order to improve a persistency of the snow-or ice-accretion inhibiting effect by preventing the organopolysiloxanesfrom suffering from bleed-out as well as peel-off upon removal of ice,compositions using a copolymer obtained by copolymerizing a specificorganosilicon compound having a hydrolyzable silyl group with anothermonomer, in combination with a hydroxy-containing resin have beenproposed (Japanese Patent Application Laid-Open (KOKAI) No. 3-84069);and compositions using a specific alkoxydimethylsiloxane (JapanesePatent Application Laid-Open (KOKAI) No. 2-147688). In addition, as awater-repellant coating composition, there has also been proposed thecomposition comprising an acrylic polymer, a silicone and afluorine-containing polymer (Japanese Patent Application Laid-Open(KOKAI) No. 10-310740).

However, these conventionally known compositions have failed to exhibitsufficient snow- or ice-accretion inhibiting effects. Thus, duringsnowfall, it is necessary to attain a good snow- or ice-accretioninhibiting effect. On the other hand, when the ambient temperatureincreases after snowfall, snow deposited on the surfaces of buildingstructures such as roofs gradually change to sticky snow having a largewater content. This sticky snow adheres to the surfaces of the buildingstructures and becomes difficult to peel off or remove. That is, aftersnowfall, there is a problem that the snow slipping-off property(reduced snow adherency) to assist in snow removal is deteriorated.Therefore, it is also necessary to improve the snow slipping-off(removal) property under such conditions. In particular, buildingstructures having a gradient of not more than 45° suffer from severesnow coverage and, therefore, are required to show improved snowslipping-off/removal properties.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the test samples and their angles from ahorizontal plane in the Examples and Comparative Examples; and

FIG. 2 is an illustration of the aluminum frame used in the Examples andComparative Examples.

DISCLOSURE OF THE INVENTION

It has been found that an excellent snow- or ice-accretion inhibitingeffect upon snowfall does not necessarily lead to an excellent snowslipping-off or removal property. As a result of further studies, it hasbeen found that although low adhesion (low icing force) between snow andthe surface of the building structure is advantageous to attain a goodsnow- or ice-accretion inhibiting effect and the snow slipping-offproperty tends to be improved by a low viscosity of water present at aninterface between snow and the building structure (lubrication action),conventionally known snow- or ice-accretion inhibiting agents fail toshow a sufficient surface hydrophilic property and, therefore, have poorsnow non-adherency or slipping-off properties.

That is, according to various aspects of the present invention, thereare provided:

(1) A composition for snow- or ice-accretion inhibiting member, having astatic friction coefficient of less than 1.3 as measured relative tosnow having a temperature range of 0 to −10° C.;

(2) A composition for snow- or ice-accretion inhibiting member, having astatic friction coefficient of less than 1.3 as measured relative tosnow having a density range of 0.2 to 0.5 g/cm³;

(3) A composition for snow- or ice-accretion inhibiting member, having astatic friction coefficient of less than 1.3 as measured relative tosnow having a water content range of 0 to 15%;

(4) A composition for snow- or ice-accretion inhibiting member, having astatic friction coefficient of less than 1.3 as measured relative tosnow having a temperature range of 0 to −10° C.;

(5) A composition for snow- or ice-accretion inhibiting member, having astatic friction coefficient of less than 1.3 as measured relative tosnow having a density range of 0.3 to 0.5 g/cm³;

(6) A composition for snow- or ice-accretion inhibiting member, having astatic friction coefficient of less than 1.3 as measured relative tosnow having a water content range of 2 to 12%;

(7) A composition for snow- or ice-accretion inhibiting member, having astatic friction coefficient of less than 1.2 as measured relative tosnow having a temperature of −0.1° C.;

(8) A composition for snow- or ice-accretion inhibiting member, having astatic friction coefficient of not more than 1.1 as measured relative tosnow having a density of 0.3 g/cm³;

(9) A composition for snow- or ice-accretion inhibiting member, having afriction coefficient of not more than 1.1 as measured relative to snowhaving a water content of 2.0%;

(10) A composition for snow- or ice-accretion inhibiting member, havinga static friction coefficient relative to snow having a temperature of−10° C. which is larger than a static friction coefficient relative tosnow having a temperature of 0° C. and which is not more than 7.5;

(11) A composition for snow- or ice-accretion inhibiting member, havinga static friction coefficient relative to snow having a density of 0.2g/cm³ which is larger than a static friction coefficient relative tosnow having a density of 0.45 g/cm³ and which is not more than 7.5; and

(12) A composition for snow- or ice-accretion inhibiting member, havinga static friction coefficient relative to snow having a water content of0% which is larger than a static friction coefficient relative to snowhaving a water content of 15% and which is not more than 7.5.

Thus, the coating composition of the present invention provides anexcellent snow-accretion inhibiting effect (reduced snow adherency) aswell as ice-accretion inhibiting effect.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be described in more detail below.

The composition of the present invention has a static frictioncoefficient of less than 1.3, preferably not more than 1.2, morepreferably not more than 1.15 as measured relative to snow having atemperature range of 0 to −10° C., snow having a density range of 0.2 to0.5 g/cm³ or snow having a water content range of 0 to 15%. Also, thecomposition of the present invention has a static friction coefficientof less than 1.3, preferably not more than 1.2, more preferably not morethan 1.1, still more preferably not more than 1.0, most preferably notmore than 0.9 as measured relative to snow having a temperature range of0 to −10° C., snow having a density range of 0.3 to 0.5 g/cm³ or snowhaving a water content range of 2 to 15%. Further, the composition ofthe present invention has a friction coefficient of not more than 1.1,preferably not more than 1.0, more preferably not more than 0.9 asmeasured relative to snow having a temperature of −0.1° C., snow havinga density of 0.3 g/cm³ or snow having a water content of 2.0%. Inaddition, the composition for a snow- or ice-accretion inhibiting memberaccording to the present invention is characterized in that the staticfriction coefficient relative to snow having a temperature of −10° C. islarger than that relative to snow having a temperature of 0° C. andwhich is not more than 7.5, preferably not more than 5, more preferablynot more than 3. Also, the composition for a snow- or ice-accretioninhibiting member according to the present invention is characterized inthat the static friction coefficient relative to snow having a densityof 0.2 g/cm³ is larger than that relative to snow having a density of0.45 g/cm³ and which is not more than 7.5, preferably not more than 5,more preferably not more than 3. Further, the composition of the presentinvention is characterized in that the static friction coefficientrelative to snow having a water content of 0% is larger than thatrelative to snow having a water content of 15% and which is not morethan 7.5, preferably not more than 5, more preferably not more than 3.

In the above-described preferred embodiments of the present invention,the static friction coefficient relative to snow having a temperaturerange of 0 to −10° C. means the range covered by the specific staticfriction coefficients relative to snows having temperatures of 0° C.,−0.1° C., −5° C. and −10° C., but does not mean the range covered bywhole static friction coefficients measured relative to whole snowshaving a temperature range of from 0° C. to −10° C. Also, the staticfriction coefficient relative to snow having a density range of 0.2 to0.5 g/cm³ means the range covered by the specific static frictioncoefficients relative to snows having densities of 0.21 g/cm³, 0.24g/cm³, 0.30 g/cm³ and 0.45 g/cm³, but does not mean the range covered bywhole static friction coefficients measured relative to whole snowshaving a density range of from 0.2 to 0.5 g/cm³. In addition, the staticfriction coefficient relative to snow having a water content range of 0to 15% means the range covered by the specific static frictioncoefficients relative to snows having water contents of 0%, 0.1%, 2.0%and 15.0%, but does not mean the range covered by whole static frictioncoefficients measured relative to whole snows having a water contentrange of from 0 to 15%. Further, the static friction coefficientrelative to snow having a temperature range of 0 to −1° C. means therange covered by the specific static friction coefficients relative tosnows having temperatures of 0° C. and −0.1° C., but does not mean therange covered by whole static friction coefficients measured relative towhole snows having a temperature range of from 0 to −1° C. In addition,the static friction coefficient relative to snow having a density rangeof 0.3 to 0.5 g/cm³ means the range covered by the specific staticfriction coefficients relative to snows having temperatures of 0.30g/cm³ and 0.45 g/cm³, but does not mean the range covered by wholestatic friction coefficients measured relative to whole snows having adensity range of from 0.3 to 0.5 g/cm³. Furthermore, the static frictioncoefficient relative to snow having a water content range of 2 to 15%means the range covered by the specific static friction coefficientsrelative to snows having water contents of 2.0% and 15.0%, but does notmean the range covered by whole static friction coefficients measuredrelative to whole snows having a water content range of from 2 to 15%.

Next, individual compounds constituting the respective compositions ofthe present invention are specifically described below.

Explanation of Silicate Component

The composition of the present invention contains an organosilicate.

The organosilicate represents compounds obtained by substituting a partor whole of hydrogen atoms of silane (SiH₄) with an organic group viaoxygen atom (hereinafter occasionally referred to as “organoxy group”).As long as such an organoxy group is present, other organic groups suchas alkyl may be bonded to the silicon atom. Examples of theorganosilicate may include organoxysilanes having 1 to 4 organic groupseach bonded to a common silicon atom via oxygen atom, andorganoxysiloxanes whose silicon constitutes a siloxane main chain((Si—O)_(n)).

The organic groups each bonded to the silicon via oxygen atom are notparticularly restricted. Examples of the organic groups may includelinear, branched or cyclic alkyl groups. Specific examples of theorganic groups may include methyl, ethyl, n-propyl, i-propyl, n-butyl,i-butyl, t-butyl, n-pentyl, i-pentyl, neopentyl, hexyl, octyl or thelike. Also, as the organic groups, there may be used fluorinated alkylgroups obtained by substituting a part or whole of hydrogen atoms ofthese alkyl groups with fluorine atoms. Especially suitable organicgroups are alkyl groups having 1 to 4 carbon atoms. As the other organicgroups, there may be used aryl, xylyl, naphthyl or the like. Two or moredifferent kinds of organic groups may be used in combination.

The above alkyl groups may be either linear or branched, and preferablyhave 1 to 4 carbon atoms. Specific examples of the alkyl groups mayinclude methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl,t-butyl or the like. Further, as the alkyl groups, there may also beused fluorinated alkyl groups obtained by substituting a part or wholeof hydrogen atoms of these alkyl groups with fluorine atoms. These alkylgroups may be used in combination of any two or more thereof.

Of these alkyl groups, methyl and/or ethyl are preferred from thestandpoint of exhibiting a reduced adherence/good snow slipping-offproperty, and the most preferred alkyl group is methyl.

When the alkyl groups have too many carbon atoms, the organosilicatetends to be deteriorated in hydrolyzability, so that the formation ofSiOH group becomes too slow when a coating film obtained from thecomposition is exposed to outside atmosphere, resulting in insufficientsnow slipping-off property.

Examples of the organoxysilanes may include tetramethoxysilane,tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane,tetraphenoxysilane, dimethoxydiethoxysilane or the like.

Examples of the organoxysiloxanes may include condensates of the aboveorganoxysilanes.

Specific examples of the preferred organosilicates used in the presentinvention may include tetraalkoxysilanes such as tetramethoxysilane,tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane,tetra-n-butoxysilane, tetraisobutoxysilane, tetra-sec-butoxysilane andtetra-t-butoxysilane, and/or partially hydrolyzed condensates thereof.The hydrolysis rate of these organosilicates is 0 to 80%, preferably 20to 70%, more preferably 30 to 60%.

Here, the hydrolysis rate is the value calculated according to thefollowing formula (II), more specifically, the value obtained from theamount of water added upon the partial hydrolytic condensation oftetraalkoxysilanes or organoalkoxysilanes. Also, the hydrolysis rate issubstantially identical to the value obtained by measuring a siloxanecondensation degree of the obtained partially-hydrolyzed condensate(i.e., a factor “m” of oxygen of the partially-hydrolyzed condensaterepresented by the formula (I)).

X_(n)Si(OR)_(4-n) +mH₂O→X_(n)Si(OR)_(4-n-2)O_(m)+2mROH  (I)

(wherein X and R are the same or different organic groups; and n is aninteger of 0 to 3)

Hydrolysis Rate=2m/(4−n)×100=m/(2−n/2)×100  (II)

In addition, a coating film formed from the above organosilicatepreferably has a water-contact angle (wetting angle) of not more than60° C. Also, in the present invention, there may be used fluorinatedorganosilicates obtained by substituting a part or all of hydrogen atomsof alkyl groups of these organosilicates and/or partially hydrolyzedcondensates thereof with fluorine atoms. These organosilicates may beused alone or in combination of any two or more thereof. Of theseorganosilicates, tetramethoxysilane and/or partially hydrolyzedcondensates thereof are preferred because these compounds can readilyform a silanol group owing to their high hydrolytic reactivity and,therefore, can readily provide a composition having a high snowslipping-off property.

As the organosilicates, there may be suitably usedpolymethoxypolysiloxanes as partially hydrolyzed condensates oftetramethoxysilane such as “MKC SILICATE MS51” and “MKC SILICATE MS56”both produced by Mitsubishi Chemical Corporation, or hydrolyzedsolutions thereof since these compounds contain a less amount ofimpurities and can exhibit an excellent safety and a stable qualitybecause the amount of high-toxic monomers contained therein issubstantially ignorable.

As described above, the organosilicates used in the present inventioninclude those obtained by substituting a part or whole of hydrogen atomsof SiH₄ with organic groups via oxygen or with other organic groups.Examples of these organosilicates may include various silane couplingagents or the like. Specific examples of the organosilicates may includetrialkoxysilane compounds such as methyl trimethoxysilane, methyltriethoxysilane, methyl tripropoxysilane, methyl triisopropoxysilane,ethyl trimethoxysilane, ethyl triethoxysilane, ethyl tripropoxysilane,ethyl triisopropoxysilane, propyl trimethoxysilane, propyltriethoxysilane, butyl trimethoxysilane, butyl triethoxysilane, pentyltrimethoxysilane, pentyl triethoxysilane, hexyl trimethoxysilane, hexyltriethoxysilane, phenyl trimethoxysilane, phenyl triethoxysilane, phenyltripropoxysilane, phenyl triisopropoxysilane, benzyl trimethoxysilane,benzyl triethoxysilane, 3-glycidoxypropyl trimethoxysilane,3-glycidoxypropyl triethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl triethoxysilane,3-methacryloxypropyl trimethoxysilane, 3-methacryloxypropyltriethoxysilane, vinyl trimethoxysilane, vinyl triethoxysilane,3-mercaptopropyl trimethoxysilane, 3-mercaptopropyl triethoxysilane,3-aminopropyl triethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-ureidopropyl triethoxysilane,1H,1H,2H,2H-perfluorohexyl trimethoxysilane, 1H,1H,2H,2H-perfluorohexyltriethoxysilane, 1H,1H,2H,2H,3H,3H-perfluorohexyl trimethoxysilane,1H,1H,2H,2H,3H,3H-perfluorohexyl triethoxysilane,1H,1H,2H,2H-perfluorooctyl trimethoxysilane, 1H,1H,2H,2H-perfluorooctyltriethoxysilane, 1H,1H,2H,2H,3H,3H-perfluorooctyl trimethoxysilane,1H,1H,2H,2H,3H,3H-perfluorooctyl triethoxysilane,1H,1H,2H,2H-perfluorodecyl trimethoxysilane, 1H,1H,2H,2H-perfluorodecyltriethoxysilane, 1H,1H,2H,2H,3H,3H-perfluorodecyl trimethoxysilane and1H,1H,2H,2H,3H,3H-perfluorodecyl triethoxysilane, and partiallyhydrolyzed condensates thereof; dialkoxysilane compounds such asdimethyl dimethoxysilane, dimethyl diethoxysilane, diethyldimethoxysilane, diethyl diethoxysilane, diphenyl dimethoxysilane,diphenyl diethoxysilane, 3-glycidoxypropylmethyl dimethoxysilane,3-methacryloxypropylmethyl dimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-aminopropylmethyl dimethoxysilane,N-(2-aminoethyl)-3-aminopropylmethyl dimethoxysilane,1H,1H,2H,2H-perfluorohexyl dimethoxymonomethylsilane,1H,1H,2H,2H-perfluorohexyl diethoxymonoethylsilane,1H,1H,2H,2H,3H,3H-perfluorohexyl dimethoxymonomethylsilane,1H,1H,2H,2H,3H,3H-perfluorohexyl diethoxymonoethylsilane,1H,1H,2H,2H-perfluorooctyl dimethoxymonomethylsilane,1H,1H,2H,2H-perfluorooctyl diethoxymonoethylsilane,1H,1H,2H,2H,3H,3H-perfluorooctyl dimethoxymonomethylsilane,1H,1H,2H,2H,3H,3H-perfluorooctyl diethoxymonoethylsilane,1H,1H,2H,2H-perfluorodecyl dimethoxymonomethylsilane,1H,1H,2H,2H-perfluorodecyl diethoxymonoethylsilane,1H,1H,2H,2H,3H,3H-perfluorodecyl dimethoxymonomethylsilane and1H,1H,2H,2H,3H,3H-perfluorodecyl diethoxymonoethylsilane, and partiallyhydrolyzed condensates thereof; chlorosilane compounds such asmethyltrichlorosilane, vinyltrichlorosilane, phenyltrichlorosilane,methyldichlorosilane, dimethyldichlorosilane, dimethylchlorosilane,methylvinyldichlorosilane, 3-chloropropylmethyldichlorosilane,diphenyldichlorosilane and methylphenyldichlorosilane, and partiallyhydrolyzed condensates thereof; 3-aminopropyl trimethoxysilane;N-3-trimethoxysilylpropyl-m-phenylene diamine;N,N-bis[3-(methyldimethoxysilyl)propyl] ethylene diamine;N,N-bis[3-(trimethoxysilyl)propyl] ethylene diamine;P-[N-(2-aminoethyl)aminomethyl] phenethyl trimethoxysilane; or the like.

The coating composition of the present invention may containorganosilicates other than those obtained by substituting all of thehydrogen atoms of SiH₄ with organoxy groups. In this case, the contentof the organosilicates other than those obtained by substituting all ofthe hydrogen atoms of SiH₄ with organoxy groups is not more than 200parts by weight, preferably not more than 150 parts by weight(calculated as SiO₂) based on 100 parts by weight of the organosilicatesobtained by substituting whole hydrogen atoms of SiH₄ with organoxygroups. When the content of the organosilicates other than thoseobtained by substituting all of the hydrogen atoms of SiH₄ with organoxygroups is too high, the obtained composition tends to have a poor snowslipping-off property.

For example, in order to enhance coatability of the composition whenforming a coating film, or prevent the occurrence of cracks in thecoating film (i.e., enhance a flexibility of the coating film), theremay be used organosilicates obtained by substituting only a part of thehydrogen atoms of SiH₄ with the above alkyl groups. The content of suchorganosilicates obtained by substituting only a part of the hydrogenatoms of SiH₄ with the above alkyl groups is 0.1 to 200 parts by weight,preferably 1 to 150 parts by weight (calculated as SiO₂) based on 100parts by weight of the organosilicates obtained by substituting all ofthe hydrogen atoms of SiH₄ with organoxy groups.

In addition, the composition of the present invention may also containsilicon compounds having hydrolyzable functional groups other than theorganoxy groups, e.g., various halogens or the like. However, suchsilicon compounds tend to produce substances such as hydrochloric acidwhich are difficult to handle upon hydrolysis thereof, thereby causingunfavorable environmental problems. Therefore, the silicon compounds arepresent in an amount of not more than 100 parts by weight, preferablynot more than 5 parts by weight (calculated as SiO₂) based on 100 partsby weight of the organosilicates. As a matter of course, the compositionof the present invention may not contain any of these silicon compounds.

When used for painting, the composition preferably shows a good filmforming-property so as to allow the composition to be rapidly cured atordinary temperature. For this purpose, the silicate component may bepreviously blended with an appropriate amount of water or a solvent suchas alcohol so as to prepare a composition capable of forming a properfilm at ordinary temperature. The addition of water or the solventenables the silicate as well as the below-mentioned hydrophobic compoundto be uniformly dispersed or dissolved therein.

The silicate component is hydrolyzed by adding water thereto to form asilanol group, to increase the hydrophilic property of the composition.

For example, when 1 to 100 parts by weight, preferably 10 to 50 parts byweight of water, and 100 to 5,000 parts by weight, preferably 500 to2,000 parts by weight of the solvent such as alcohol are blended in 100parts by weight of the silicate component, the obtained compositionshows an excellent coatability. For example, water and the solvent arepreviously blended with the silicate component to prepare a hydrolyzedsolution of the silicate component. Then, the resultant solution ismixed with the below-mentioned hydrophobic compound and, if required,with an appropriate amount of solvent, or may be mixed with thehydrophobic compound previously dispersed or dissolved in the solvent.

The composition of the present invention in the form of a coatingsolution may also include one or more of the components explained below.

Explanation of Hydrophobic Compound

The hydrophobic compound is a component capable of imparting ahydrophobic property to the composition as compared to the use of asilicate alone. Specifically, there may be suitably used at least onehydrophobic compound selected from the group consisting of nonionicsurfactants, fluorine-based surfactants, fluororesin powder, siliconresin powder and silicone-based surfactants.

The hydrophobic compound preferably exhibits a critical surface tensionof not more than 20 mPa·s.

Examples of the nonionic surfactants include polyoxyethylene alkylethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene sorbitanfatty acid esters, sorbitan fatty acid esters or the like. Examples ofthe fluorine-based surfactants include perfluoroalkyl-containingperfluoroalkyl oligomers such as oligomers of perfluoroalkyl carboxylicacid salts, perfluoroalkyl phosphoric acid esters and perfluoroalkylammonium salts; perfluoroethyleneoxide adducts; perfluorocarboxylic acidsalts; or the like. For example, as the fluorine-based surfactants,there may be used “SC-101” and “SC- 105” both produced by Asahi GlassCo., Ltd.

Examples of the fluororesin powder include low-molecular weight ethylenetetrafluoride polymers, more specifically, perfluoro compounds having anaverage molecular weight of preferably 1,500 to 20,000, more preferably500 to 15,000, and a particle diameter of preferably 0.1 to 20 μm, morepreferably 0.1 to 1 μm.

The silicon resin powder has an average particle diameter of preferably0.1 to 20 μm, more preferably 0.1 to 1 μm. Examples of thesilicone-based surfactants include those containing methylpolysiloxaneas a hydrophobic group and polyalkyleneoxide as a hydrophilic group. Forexample, there may be suitably used “SILWET L-7001” produced by NipponUnicar Co., Ltd.

Of these hydrophobic compounds, the fluorine-based surfactants arepreferred because the excellent effect can be attained by using thefluorine-based surfactants in combination with the organosilicates,though the reason therefor is not clearly known.

The composition of the solvent used for preparation of the silicatesolution may be appropriately controlled according to the kind ofhydrophobic compound used so as to uniformly disperse the hydrophobiccompound and the silicate therein.

Blending Ratio of Silicate to Hydrophobic Compound

The hydrophobic compound may be suitably contained in an amount of 0.1to 100 parts by weight, preferably 1 to 50 parts by weight based on 100parts by weight of the silicate. When the content of the hydrophobiccompound is less than 0.1 part by weight, the obtained composition tendsto show a low snow-accretion inhibiting effect. When the content of thehydrophobic compound is more than 100 parts by weight, the coating filmobtained from the composition tends to be deteriorated in strength andadhesion to a substrate.

The use of the silicate according to the present invention can enhance asnow slipping-off property of the obtained composition. In addition,when the silicate is used in combination with the hydrophobic materialsuch as fluororesin, the obtained composition can be further enhanced inits snow-accretion inhibiting property.

The solution containing the silicate, water, the solvent and thehydrophobic compound has a silicate concentration of preferably not lessthan 0.05% by weight, more preferably not less than 0.1% by weight(calculated as SiO₂). When the silicate concentration is less than 0.05%by weight, the obtained composition tends to become poor in snowslipping-off property. In addition, even when the silicate is used incombination with the fluororesin, the obtained composition fails toexhibit a sufficient snow-accretion inhibiting property.

The snow slipping-off property of the composition as well as thesnow-accretion inhibiting property thereof when used in combination withthe hydrophobic material such as fluororesins, are considerablyinfluenced by the silicate concentration in solid components(non-volatile components) calculated as SiO₂. The silicate concentrationin the solid components (non-volatile components) calculated as SiO₂ ispreferably not less than 15% by weight, more preferably not less than25% by weight. When the silicate concentration in solid components isless than 15% by weight, the obtained composition tends to become poorin snow slipping-off property, and even when the silicate is used incombination with the hydrophobic material such as fluororesins, thecomposition fails to exhibit a sufficient snow-accretion inhibitingproperty.

When it is required to obtain a coating film having an improved adhesionto a substrate and a good flexibility for preventing occurrence ofcracks, appropriate resin components such as acrylic resins and othercomponents may be added to the composition.

Examples of the acrylic resins may include ordinary acrylic resins suchas methyl methacrylate polymers.

The above-described liquid composition may be applied onto varioussubstrates. The substrates are not particularly restricted, and theremay be used any materials capable of forming a coating film thereon,such as roofs or other structural materials. More specifically, thecomposition of the present invention can be suitably applied toconstructions or structures mainly including roofs, electric cables,steel towers for electric cables, road signs or the like which requiresnow- or ice-accretion inhibiting properties as well as those having asurface inclined at an angle of not more than 45° from horizontal and,therefore, requiring a good snow slipping-off property.

EXAMPLES

The present invention is described in more detail by the followingexamples.

Measurement of Snow Temperature

The snow temperature was measured by K thermocouple-type digitalthermometer “TNA-120” manufactured by Tasco Japan Co., Ltd.

Measurement of Snow Density

Snow blocks were sampled to measure weight and volume thereof. The snowvolume was measured by a “Snow Sampler” (rectangular cup) capable ofsampling 200 cc of snow, and the snow weight was measured by anelectronic balance.

Measurement of Static Friction Force and Calculation of Static FrictionCoefficient

Coating solutions obtained in the below-mentioned Preparation Examples 1to 5 were respectively applied onto an aluminum plate (tradename“A1050P” produced by Engineering Test Service Co., Ltd.; according toJIS H4000; surface roughness: 0.5 μm; length: 50 cm; width: 50 cm;thickness: 2 mm) using a roller (“Small Roller Model 6S-C113”manufactured by Otsuka Brush Co., Ltd.) to form a coating film having adry thickness of about 2 μm. The coating films thus obtained using therespective coating solutions were used as samples of Examples 1 to 3 andComparative Examples 1 and 2, respectively. Further, an uncoated glassplate (reinforced glass plate produced by Engineering Test Service Co.,Ltd.; according to JIS R3206; surface roughness: 0.5 μm; length: 50 cm;width: 50 cm; thickness: 2 mm) was used as a sample of ComparativeExample 3, and a Teflon plate (Teflon (polytetrafluoroethylene resin)produced by Engineering Test Service Co., Ltd.) was used as a sample ofComparative Example 4.

These samples were subjected to measurement of friction force relativeto snow by the following method. The results are shown in Table 1.

(1) The test plates were set on a horizontal plane within alow-temperature room (laboratory capable of being controlled to atemperature of 0° C. or lower, and changing an inside temperaturethereof at intervals of 0.1° C.).

(2) Snow having a snow temperature of −10° C. was deposited at a heightof about 5 cm on the respective test plates under an ambient temperaturecondition of −10° C. Also, the test plates set on such a place where nosnow was deposited, were used as blanks.

(The snow deposited on the test plates was an artificial snow preparedby scratching off “frost” formed by blowing steam onto a membrane. Thesnow has an average diameter (crystal size) of 0.025 mm, and a snowquality corresponding to a fresh snow having a density of about 0.2g/ml. The test was conducted using a test device manufactured by ToyoSeisakusho Co., Ltd.)

(3) After completion of snowfall, the test plates were allowed to standfor one hour, and subjected to measurement of friction force.

(4) An aluminum frame (configuration of the aluminum frame is shown inFIG. 2; tare weight: 120 g; frame inner volume: 1,000 cc) was pushed inthe snow deposited on each test plate to be measured without causing thesnow to move thereon until coming into contact with the test plate.

(5) The snow attached to an upper portion of the aluminum frame wasremoved, and a measuring device (spring balance: push-pull gauge) wasfitted thereto.

(6) The aluminum frame was pulled at a constant speed of about 10mm/min. A pulling force A at which the aluminum frame was first movedand a pulling force B for the test plates as blanks on which no snow wasdeposited, were respectively measured to calculate a friction force(A-B).

(7) The weight C of the snow received within the aluminum frame used formeasuring the above friction force was measured by an electronicbalance. In addition, the water content D in the snow was measured by anInnsbruck-type water content meter.

(8) After the ambient temperature was raised to −5° C., the test plateswere maintained under this condition for one hour, and then the aboveprocedures (4) to (7) were repeated.

(9) After the ambient temperature was further raised to −0.1° C., thetest plates were maintained under this condition for one hour, and thenthe above procedures (4) to (7) were repeated.

(10) After the ambient temperature was further raised to 0° C., the testplates were maintained under this condition for one hour, and then theabove procedures (4) to (7) were repeated.

Calculation of Static Friction Coefficient:

The static friction coefficient under each of the above conditions wascalculated from the static friction force and the snow weight Caccording to the following formula:

(Static Friction Coefficient)=(Static Friction Force)/C

Composition

Meanwhile, “MKC SILICATE MS51” produced by Mitsubishi ChemicalCorporation. (hydrolysis rate: 40%) was used as the organosilicate.Also, the composition of the “mixed solvent” used during the formulationwas as follows.

TABLE 2 Toluene 23 parts by weight Propylene glycol monomethyl etheracetate 18 parts by weight Butyl acetate 12.5 parts by weight Methylisobutyl ketone 9 parts by weight Propylene glycol monomethyl ether 22.5parts by weight n-butanol 7.5 parts by weight Isopropyl alcohol 7.5parts by weight Total 100.0 parts by weight

Preparation Example 1

Hydrolyzed solution of organosilicate (*1) 118 parts by weight Note *1:The composition of the hydrolyzed solution of organosilicate was asfollows. Mixed solvent 100 parts by weight Organosilicate 16 parts byweight 10% hydrochloric acid solution 2.0 parts by weight

Preparation Example 2

Formulation:

Hydrolyzed solution of organosilicate (*1) 118 parts by weight SC-101(*2) 4.8 parts by weight (corresponding to 10% by weight as a solidcontent based on the weight of the silicate contained in the hydrolyzedsolution) Note: *2: Fluorine-based surfactant produced by Asahi GlassCo., Ltd.

Preparation Example 3

Formulation:

Hydrolyzed solution of organosilicate (*1) 118 parts by weight SILWETL-7001 (*3) 1.6 parts by weight (corresponding to 10% by weight as asolid content based on the weight of the silicate contained in thehydrolyzed solution) Note: *1: The composition of the hydrolyzedsolution of organosilicate was the same as used in PreparationExample 1. *3: Silicone-based surfactant produced by Nippon Unicar Co.,Ltd.

Preparation Example 4

Cold-curing type fluororesin paint 100 parts by weight (vinylidenefluoride-based paint)

Preparation Example 5

Cold-curing type fluororesin paint (vinylidene 100 parts by weightfluoride-based paint) SILWET L-7001 2.5 parts by weight (correspondingto 10% by weight as a solid content based on the weight of solidcomponents of the fluororesin paint)

Examples 1 to 3 and Comparative Examples 1 to 4

Aluminum plates were respectively coated with the coating solutionsprepared in Preparation Examples 1 to 5 to produce samples of Examples 1to 3 and samples of Comparative Examples 1 and 2. An uncoated glassplate was used as a sample of Comparative Example 3, and a Teflon plate(Teflon: registered trademark; tetrafluoroethylene polymer) was used asa sample of Comparative Example 4. Three samples were prepared for eachcoating solution. The three samples were set at angles of 10°, 30° and45° from a horizontal plane, respectively. Three uncoated glass platesand three Teflon plates were respectively set at the same angles asabove. The outline of the test is shown in FIG. 1 wherein (1) denotessamples held at an angle of 10°; (2) denotes samples held at an angle of30°; and (3) denotes samples held at an angle of 45°.

These samples were subjected to snowfall test under the followingconditions.

First Day

21:30 Initiation of snowfall (ambient temperature: −8° C. to −10° C.)

Second Day

8:00 Termination of snowfall 9:00 Initiation of temperature rise (untilthe ambient temperature was raised to 5° C.)

14:00 Termination of snowfall test

Results of Experiments:

During the snowfall test, among the test plates coated with the coatingsolution prepared in Preparation Example 2, the test plate set at anangle of 45° was free from snow accretion thereon, and the test platesset at angles of 30° and 10° were covered with snow. On the other hand,the test plates coated with the coating solutions prepared inPreparation Examples 1, 3, 4 and 5 as well as the Teflon plates, roofsteel plates and glass plates were covered with snow at every settingangles.

When the ambient temperature was raised, snow was dropped off from thetest plates in the following order for a period between 10:15 to 13:00.

10:15 Among the test plates coated with the coating solution prepared inPreparation Example 2, snow was dropped-off from the test plate set atan angle of 30°.

10:30 Snow was dropped-off from the test plates set at angles of 45° and30° among those coated with the coating solution prepared in PreparationExample 1; the test plates set at angles of 45° and 30° among thosecoated with the coating solution prepared in Preparation Example 3; andthe glass plate set at an angle of 45°.

11:00 Snow was dropped-off from the test plates set at angles of 45° and30° among those coated with the coating solution prepared in PreparationExample 4; the test plates set at angles of 45° and 30° among thosecoated with the coating solution prepared in Preparation Example 5; andthe glass plate set at an angle of 30°.

12:00 Snow was dropped-off from the Teflon plate set at an angle of 45°;the glass plate set at an angle of 10°; the test plate set at an angleof 10° among those coated with the coating solution prepared inPreparation Example 2; the test plate set at an angle of 100 among thosecoated with the coating solution prepared in Preparation Example 1; andthe test plate set at an angle of 10° among those coated with thecoating solution prepared in Preparation Example 3.

12:30 Snow was dropped-off from the Teflon plate set at an angle of 30°;and the roof steel plate set at an angle of 45°.

13:00 Snow was dropped-off from the roof steel plate set at an angle of30°.

13:30 Termination of test

As a result, it was confirmed that snow deposited on the test plates setat an angle of 10’ among those coated with the coating solutionsprepared in Preparation Examples 4 and 5 as well as the Teflon plate andthe roof steel plate set at an angle of 10°, was not dropped-off untilthe test was finally terminated, and these test plates were stillcovered with snow.

Considerations from the Test Results

(1) Snow- and ice-accretion inhibiting effect:

The test plates used in Example 2 (which were coated with the solutionprepared in Preparation Example 2 by using the organosilicate incombination with the hydrophobic compound), were free from snow coverageduring the snowfall test. As a result, it was confirmed that the coatingcomposition used in Example 2 showed an excellent snow-accretioninhibiting effect.

(2) Snow Slipping-off Effect

The test plates used in Example 2 as well as the test plates used inExample 1 (which were coated with the hydrolyzed solution oforganosilicate prepared in Preparation Example 1), exhibited a highersnow slipping-off property (earlier snow-slippage) as compared to thoseused in Comparative Examples even though the setting angle of Exampleswas smaller than that of Comparative Examples. As a result, it wasconfirmed that the coating compositions used in these Examples were moreeffective than those used in Comparative Examples.

From the above descriptions, it is recognized that the composition canbe improved in snow slipping-off property by adding the organosilicatethereto; and the composition using the organosilicate in combinationwith the hydrophobic compound can show an improved snow slipping-offproperty and simultaneously can be prevented from undergoing snowcoverage upon snowfall and, therefore, is excellent in both of snowslipping-off property and snow- or ice-accretion inhibiting property.

TABLE 1 Examples Comparative Example 1 2 3 1 2 3 4 Snow A g 255 210 245200 190 1870 175 temp. B g 15 10 10 10 10 20 10 −10° C. Static frictionforce g 240 200 230 190 180 1850 170 Snow weight C g 210 210 210 210 210210 210 Density g/ 0.21 0.21 0.21 0.21 0.21 0.21 0.21 Water content D %0 0 0 0 0 0 0 Static friction coefficient 1.14 0.95 1.10 0.90 0.86 8.810.81 Snow A g 280 240 265 255 245 1360 230 temp. B g 15 10 15 15 10 2010 −5° C. Static friction force g 265 230 250 240 235 1340 220 Snowweight C g 240 240 240 240 240 240 240 Density g/ 0.24 0.24 0.24 0.240.24 0.24 0.24 Water content D % 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Staticfriction coefficient 1.10 0.96 1.04 1.00 0.98 5.58 0.92 Snow A g 280 275275 380 410 415 440 temp. B g 10 10 10 15 15 15 15 −0.1° C. Staticfriction force g 270 265 265 365 395 400 425 Snow weight C g 300 300 300300 300 300 300 Density g/ 0.30 0.30 0.30 0.30 0.30 0.30 0.30 Watercontent D % 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Static friction coefficient 0.900.88 0.88 1.22 1.32 1.34 1.42 Snow A g 370 360 365 605 650 400 680 temp.B g 10 10 10 15 15 15 15 −0° C. Static friction force g 360 350 355 590635 385 665 Snow weight C g 450 450 450 450 450 450 450 Density g/ 0.450.45 0.45 0.45 0.45 0.45 0.45 Water content D % 15.0 15.0 15.0 15.5 15.515.5 15.0 Static friction coefficient 0.80 0.78 0.79 1.31 1.41 0.86 1.48

INDUSTRIAL APPLICABILITY

In accordance with the present invention, it is possible to obtain acoating composition capable of showing not only a good snow- orice-accretion inhibiting property upon snowfall but also an improvedsnow slipping-off property upon temperature rise.

What is claimed is:
 1. A snow- or ice-accretion inhibiting composition,having a static friction coefficient of less than 1.3 as measuredrelative to snow having a temperature range of 0 to −10° C. andcontaining a partially hydrolyzed condensate of an organosilicate and ahydrophobic compound.
 2. A snow- or ice-accretion inhibitingcomposition, having a static friction coefficient of less than 1.3 asmeasured relative to snow having a density range of 0.2 to 0.5 g/cm³ andcontaining a partially hydrolyzed condensate of an organosilicate and ahydrophobic compound.
 3. A snow- or ice-accretion inhibitingcomposition, having a static friction coefficient of less than 1.3 asmeasured relative to snow having a water content range of 0 to 15% andcontaining a partially hydrolyzed condensate of an organosilicate and ahydrophobic compound.
 4. A snow- or ice-accretion inhibitingcomposition, having a static friction coefficient of less than 1.3 asmeasured relative to snow having a temperature range of 0 to −1° C. andcontaining a partially hydrolyzed condensate of an organosilicate and ahydrophobic compound.
 5. A snow- or ice-accretion inhibitingcomposition, having a static friction coefficient of less than 1.3 asmeasured relative to snow having a density of 0.3 to 0.5 g/cm³ andcontaining a partially hydrolyzed condensate of an organosilicate and ahydrophobic compound.
 6. A snow- or ice-accretion inhibitingcomposition, having a static friction coefficient of less than 1.3 asmeasured relative to snow having a water content range of 2 to 15% andcontaining a partially hydrolyzed condensate of an organosilicate and ahydrophobic compound.
 7. A snow- or ice-accretion inhibitingcomposition, having a static friction coefficient of less than 1.2 asmeasured relative to snow having a temperature of −0.1° C. andcontaining a partially hydrolyzed condensate of an organosilicate and ahydrophobic compound.
 8. A a snow- or ice-accretion inhibitingcomposition, having a static friction coefficient of not more than 1.1as measured relative to snow having a density of 0.3 g/cm³ andcontaining a partially hydrolyzed condensate of an oroanosilicate and ahydrophobic compound.
 9. A snow- or ice-accretion inhibitingcomposition, having a friction coefficient of not more than 1.1 asmeasured relative to snow having a water content of 2.0% and containinga partially hydrolyzed condensate of an organosilicate and a hydrophobiccompound.
 10. A snow- or ice-accretion inhibiting composition, having astatic friction coefficient relative to snow having a temperature of−10° C. which is larger than a static friction coefficient relative tosnow having a temperature of 0° C. and which is not more than 7.5 andcontaining a partially hydrolyzed condensate of an organosilicate and ahydrophobic compound.
 11. A snow- or ice-accretion inhibitingcomposition, having a static friction coefficient relative to snowhaving a density of 0.2 g/cm³ which is larger than a static frictioncoefficient relative to snow having a density of 0.45 g/cm³ and which isnot more than 7.5 and containing a partially hydrolyzed condensate of anorganosilicate and a hydrophobic compound.
 12. A a snow- orice-accretion inhibiting composition, having a static frictioncoefficient relative to snow having a water content of 0% which islarger than a static friction coefficient relative to snow having awater content of 15% and which is not more than 7.5 and containing apartially hydrolyzed condensate of an organosilicate and a hydrophobiccompound.
 13. A composition according to any one of claims 1-12, whereinsaid partially hydrolyzed condensate of the organosilicate has ahydrolysis rate of 0 to 80%.
 14. A composition according to claim 13,wherein a coating film formed from said partially hydrolyzed condensateof the organosilicate has a water contact angle of not more than 60°.15. A composition according to any one of claims 1-12, wherein saidhydrophobic compound is a fluororesin powder.
 16. A compositionaccording to any one of claims 1-12, wherein said hydrophobic compoundis a surfactant having a perfluoroalkyl group.
 17. A compositionaccording to any one of claims 1-12, wherein said hydrophobic compoundhas a critical surface tension of not more than 20 mpa·s.
 18. A paintcomprising the composition according to any one of claims 1-12.
 19. Asnow- or ice-accretion inhibiting member coated with the paint accordingto claim 18.